Fans are on 24/7 while running
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
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From: Strongsville Ohio
Fans are on 24/7 while running
94 6spd. I was cleaning up engine bay and checking things out. I noticed my AC fans are running the whole time while the car is running. The a/c is off inside the car but the fans are running...?
I am hoping its a relay. I had my car tuned when I put the new motor in and the guy never mentioned turning the fans on early or even at all 24/7. So I know its not tuned to run like this.
Any info or help? Where the relay is?
I am hoping its a relay. I had my car tuned when I put the new motor in and the guy never mentioned turning the fans on early or even at all 24/7. So I know its not tuned to run like this.
Any info or help? Where the relay is?
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
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From: Strongsville Ohio
I havent gotten a chance to check the relays if they are bad. I checked out my coolant temp sensor in the front of the water pump and its connected good. Would the fans on the whole time pull HP from the car?
Should I just replace the 2 relays ? how do I check to see if the relays are bad?
Should I just replace the 2 relays ? how do I check to see if the relays are bad?
Racer
Joined: Oct 2010
Posts: 414
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From: Phoenix Arizona
After I had my LS3 Hot Cam crate engine installed about 15 months ago, I developed a minor problem where sometime the fans would not come on when they should. Caused a severe problem with my AC compressor one time. So I had a manual override switch installed under the hood and now I run the fans all the time unless it is really cool outside (a rare event here in AZ). My builder said that other than working the alternator a little harder than usual, running the fans 24/7 does not hurt at all. Only power drain is the extra hp used by the alternator. This is a much smaller problem for me than running the risk that my fans will not come on when they are needed. Just my 2 cents worth.
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
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From: Strongsville Ohio
I was thinking its better to have the fans working then not. I remeber sitting in traffic or even at a light and have it run to super high temps. That made me nervous and I would sweat. I will leave them running. Its nice to leave the car running while sitting somewhere for a couple mins to 10 mins and come back to it being only 201 degrees. I wish I could let them run a low instead of high but who cares. I will replace the fan motors if they go. Can I wire a switch to turn them off while driving in the current situation I have it? Or should I figure out why they are running all the time then start there?
I think my tuner wired both coolant temp sensors together for some reason a year ago. Would that cause this issue?
I think my tuner wired both coolant temp sensors together for some reason a year ago. Would that cause this issue?
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Racer
Joined: Oct 2010
Posts: 414
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From: Phoenix Arizona
When my build hot wired the fans they installed the override switch under the hood just above the battery. I could have had them install the switch under the dash but I thought I really didn't need to have access to it all the time. After using it for a while I wish I had it installed in the cabin. They wired mine directly into the relays on the side of the radiator shroud which, as they explained it to me, by passes all the other controls. When I switch it on, the fans run constantly. When I switch it off, the fans will, or should, turn off and on by themselves the way they are designed to. Only problem with my build was that they didn't always come on when they were supposed to. Not a problem now but I wish the switch was under the dash. Live and learn.
Next time the car is in the shop, this switch will be moved to the center counsel so I can control the fans all the time. Will cost a little, but well worth it to me.
Next time the car is in the shop, this switch will be moved to the center counsel so I can control the fans all the time. Will cost a little, but well worth it to me.
Last edited by C4orce2; Oct 20, 2011 at 02:28 PM.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Its nice to leave the car running while sitting somewhere for a couple mins to 10 mins and come back to it being only 201 degrees. I wish I could let them run a low instead of high
Can I wire a switch to turn them off while driving in the current situation I have it?
Or should I figure out why they are running all the time then start there?
Can I wire a switch to turn them off while driving in the current situation I have it?
Or should I figure out why they are running all the time then start there?
http://www.racerpartswholesale.com/p...n_Accessories2
If you splice it into existing relay control wiring it will run to drop temps but fan will still have ECM control if it fails.
No need to remember to switch on/ off a switch
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
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From: Strongsville Ohio
there are 3 wires coming out of the temp sensor in the water pump, one of the wires is connected to the other sensor on the passenger side block which I believe only has 2 wires. Would this make my fans both run all the time, or would this be my fan relays that are bad?
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
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From: Strongsville Ohio
I checked the coolant wires. The water pump coolant temp sensor, there are 3 wires, black, blue and white. The blue one is roued to the other temp sensor on the passenger side block. Should this wire not be wired this way? My tuner did that I guess to get both readings the same. I have not yet checked the relays. I am trying t get the fans not to run 24/7 then wire a switch in.
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
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From: Strongsville Ohio
I just stopped at advanced auto and got a new pigtail for the tem sensor in the front of the block. Anyone know what they passeneger side temp sensor looks like/pigtail ? How many wires.
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
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From: Strongsville Ohio
ok, so I have 3 wires coming out of the front temp sensor, where the heck could the 3rd wire be running to from the sensor? The wire from the front, from what I remember ties into a wire coming out the the wire harness that runs the pass side temp sensor. I will jack it up tomorrow and check this out.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
You appear to have the wiring for the ECM cross connected with wiring for temp gauge ;
two completely independent systems.
Do any of the wires at WP connect to the yellow and black wires in harness mentioned above?
Is the front sensor THE correct one ; only has two terminals
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
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From: Strongsville Ohio
well for sure the front sensor is not the correct one since it is supposed to have only two wires coming out of it. And yes the black and yellow wires are connected to the correct harness ( going towards the ICM/Coil)
Its just that the third wire from this unknown sensor is going from the wp ( starting) to somewhere around the pass side block, by the oil dipstick. I will have to jack it up and look under the car to see where its going to. Only thing I can think of is that the tuner tried or DID put a thermostat in the waterpump and that it operates the fans all the time.
I am more frustrated more then you. hang in there I will post back pics and info on whats going on.
Its just that the third wire from this unknown sensor is going from the wp ( starting) to somewhere around the pass side block, by the oil dipstick. I will have to jack it up and look under the car to see where its going to. Only thing I can think of is that the tuner tried or DID put a thermostat in the waterpump and that it operates the fans all the time.
I am more frustrated more then you. hang in there I will post back pics and info on whats going on.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Trying to get my head around why sender would be hooked up to temp gauge.
EUREKA moment.
There is a later model GM 3 wire unit ( # 10096181) that contains both an isolated 2-wire sensing element (CTS) for the ECM,
and a ground-referenced one-wire sensing element for the temp gauge sender
so most likely that is what you have.
Would explain why a wire runs to temp gauge wiring and why your engine still runs fine
(other than fan problem ) because if unit in WP was a fan switch it would have the wrong output signal as required by the ECM
Last edited by rodj; Oct 18, 2011 at 07:16 PM.